Means of skimming a pool by use of vortex

ABSTRACT

A vortex-producing chamber has an inlet from the surface of a pool and an outlet at the bottom of the vortex chamber. A vortex is formed at this outlet which carries the water with any floating debris and the like with it into a tank from which it can be drawn out by action of a suction pump. In the usual arrangement, means such as a float is located in an upper portion of the tank at the water surface. If the tank water level drops abnormally low the float means comes down with the water and engages a seat dividing the upper and lower tank portions from each other and sealing the lower tank portion from air in the upper portion. A bypass conduit leading from a water source such as the pool itself supplies water to the lower tank portion to supply the pump demand when the lower portion is thus sealed from the upper portion.

Unite tates Patent 1 mama 3,306,448 2/1967 Balter 3,508,661 4/1970Diernondetal. .7

ABSTRACT: A vortex-producing chamber has an inlet from the surface of apool and an outlet at the bottom of the vortex chamber. A vortex isformed at this outlet which carries the water with any floating debrisand the like with it into a tank from which it can be drawn out byaction of a suction pump. In the usual arrangement, means such as afloat is located in an upper portion of the tank at the water surface.If the tank water level drops abnormally low the float means comes downwith the water and engages a seat dividing the upper and lower tankportions from each other and sealing the lower tank portion from air inthe upper portion. A bypass conduit leading from a water source such asthe pooli itself supplies water to the lower tank portion to supply thepump demand when the lower portion is thus sealed from the upperportion.

PUMP

//VLET PATENTED SE82] l9?! SHEET 2 BF 2 INVENTOK 04 W0 ,4. 574/VW000ATTORNEYS MEANS OF SKIMIMIING A POOL BY USE OF VORTEX This inventionrelates to pool equipment, and particularly to means and method ofskimming surface water of a pool for removal of debris.

Proper cleaning of the water of a pool such as a swimming pool dependsin large measure on circulating and filtering the water drawn over askimming ledge and into a tank generally referred to as a skim tank.Floating debris and the like thus passes out of the pool and can becollected in a suitable basket. Due to factors such as evaporation andsplashing, followed by refilling the pool, the level of water in a poolis not maintained constant. In order to maintain proper flow from thesurface of the pool to the filter despite changes of height of the waterin the pool, weirs, for example, floating weirs have been used.

In such arrangements, the water passing over the skimming weir isreceived in the tank, which supplies the inlet of a pump which does therecirculating. The floating weir is pivoted on a horizontal axis, and isresponsive to the level of water in the tank, and it operates to keepthe level constant for any given flow rate determined by the pump. Theweir performs this function over an ordinary range of variation of poolwater level.

While this arrangement is operative throughout a substantial variationin the height of water in the pool, nevertheless there are limits to therange of operation of the floating weir. Thus, the level in the swimmingpool may drop below the opening that feeds the weir, or so close to theweir axis, that the weir can no longer increase flows by lowering. Insuch circumstances, the tank will run dry and the pump will suck air.Apart from possible damage to the pump, this creates a nuisance as faras restarting the system is concerned.

In Baker US. Pat. Nos. 3,067,879 and 3,306,448, issued Dec. II, 1962 andFeb. 28, I967, respectively, there are shown and described skim tankswhose entrance throats are provided with floating weirs which functionin this manner. These skim tanks protect automatically against the pumpsucking air by closing a portion of the tank connected to the pump inletautomatically in response to the cessation of skimming action. Thesuction thus created in the tank portion in turn produces substantialbypass flow from an equalizer line or from the main drain as the casemay be, and the pump accordingly is protected. By deliberate selection,the tank portion can be closed whatever the condition of the level inthe swimming pool might be, in order to create suction for inductingflow through a vacuum line, for example.

In Baker US. Pat. No. 3,067,879, the specific means for closing offaportion of the tank to prevent sucking of air is the floating weiritself, which when the pool water level becomes too low, drops down on aseat to cover an opening to the tank. In Baker US. Pat. No. 3,306,448,the means for closing offthe portion of the tank to prevent sucking aircomprises in one embodiment a float in the form ofa ball mounted on aguided rod which is vertically slidable so that the ball drops down on aseat, and in other embodiments by a toroidally shaped float restrainedfrom floating away by a cage, so that the float drops down on a seat,when the water level becomes too low.

Mechanical weirs such as floating weirs, although generallysatisfactory, have sometimes given trouble due to such factors asphysical breakage of the weir, or binding in the throat or entrance tothe skim tank resulting in failure to rise and lower with the waterlevel as well as might be desired, and the like.

An object of the present invention is to provide a skimming arrangementwhich does not require the use of a physical or mechanical weir such asa floating weir or the like.

In accordance with the present invention there is provided at the throatof the skimmer where the water enters from the pool, a vortexingstructure which carries the water with its floating debris down througha vortex to a location or receptacle outside the pool.

According to a preferred feature the water carried through the exitconduit from the vortex is brought to a tank from where it can be pumpedto circulate the water through a filter and back to the pool in awell-known manner. The vortexing structure is configured to produce thevortex which culminates at the exit conduit from the vortexingstructure.

The tank to which the vortex water is carried is preferably a type whichwill shut off from the atmosphere the water in the tank which is to bedrawn by the pump. This can be done by use of a suitable float orstopper which comes down on a seat to shut of? communication between alower portion of the tank and the atmosphere in the usual way.

In the use of such an arrangement, when the circulating water pump isshut down, the water level in the tank as well as in the vortexingstructure will come to the pool water level, and any floating debriscaptured in the tank will rise up to the surface of the water in thetank, allowing little or none of it to come back to the pool through theexit conduit from the vortexing structure. Any nonfloating debris in thetank will drop, and assuming the presence of the usual debris basket inthe tank, will be deposited in the basket.

The foregoing and other features of the invention will be betterunderstood from the following detailed description and the accompanyingdrawings of which:

FIG. 1 illustrates a vertical sectional view of an automatic skimmingarrangement embodying this invention, taken at line ll--ll of FIG. 2;

FIG. 2 is a transverse sectional view taken at line 2-2 of FIG. 1;

FIG. 3 illustrates a liquid vortex obtained by the arrangement of FIGS.l and 2;

FIG. 4 is a vertical sectional view of a modified form of tank useablewith the vortexing arrangement shown in FIGS. 1 and 2; and

FIG. 5 is a partial sectional view showing the tank of FIG. 4 during acondition of abnormally low water level.

In FIG. 1 there is illustrated a swimming pool wall 10, having avertical surface ill exposed to the water in the pool. A tank 12 may beembedded adjacent to or in the wall 110, and is adapted to receive waterwithdrawn from the upper surface of the pool,

In the present example, the tank 12 comprises two tank parts l3 and 14,which are upper and lower tank portions, respectively. The lower tankpart 14 has an upper opening defined by an annular angle flange 15. Theupper part has a lower opening defined by circular walls received withinthe angle flange 15.

The upper open end of the tank part 13 telescopes within a frame 16 thatis carefully set in the decking l7 adjoining the top of the swimmingpool wall 10. Alternatively, nd as will be more fully understoodhereinafter, tank 12 may be positioned some distance from wall 11 of thepool. A removable cover I8 seated upon the frame 16 provides access tothe interior of the tank 12 as may be required. I

There is set within the decking between the upper tank por tion 13 andthe vertical wall ill of the pool a chamber 19, constructed to produce avortex. Chamber i9 is enclosed on all sides except for its entranceopening 20 which registers with an opening in vertical pool wall. Thenormal pool water level 22 is at a position inten'nediate between theupper and lower walls ofopening 20; hence, it enters into chamber 19 ata level intermediate between the upper wall or ceiling 23 and theentrance floor 24 at the entrance of the chamber. The forward orupstream end of the entrance floor 24 registers with the lowermostportion of opening 20. The floor of the interior part of chamber 19 backof the entrance floor, is in the form of a frustum of a cone 25 whoseapex is at the center, the cone tapering downwardly and inwardly towardthe center to meet the opening of an exit conduit 26. The portion of theentrance 20 to the vortex chamber which is above the entrance floor 24and the conical chamber floor 25, is defined by a wall member 27 whichrises vertically from the floors to the ceiling 23 of the chamber. Theshape of this wall 27 is indicated in FIG. 2, the portion 270 around thepart of the cone back of the entrance 20 being cylindrical, the part 27bextending from the cylindrical portion to one side of the entrance 20being straight and the part 27c extending from the cylindrical part alsobeing straight but approximately perpendicular to part 27b, therebyproviding a wide entrance paths along the entrance floor 24. Theentrance floor 24 slopes downwardly from entrance 20 to its outer, uppercircumferential rim 30.

The circulating pump (not shown) withdraws water from the tank 12. Forthis purpose, the side of the lower tank portion 14, near the bottomthereof, has a conduit fitting 34 cooperable with a conduit 35 thatleads to the pump inlet, as indicated by the arrow labeled Pump Inlet."

A removable debris-collecting basket 37 having a rim resting on theannular flange serves to collect debris and prevent it from passingthrough conduit 35 to the pump. The bottom and sides of the basket areformed of a suitable perforate or screening material which will allowsubstantially unimpeded flow of water through it while retaining thedebris.

When the water level 22a in the tank drops significantly, a portion ofthe tank above the conduit fitting 24 must be sealed to prevent the pumpfrom sucking air. For this purpose there is provided a floatable body 38within the upper tank portion 13 above the basket 37. This is a flatcircular disclike member comprising a wall 39 forming and enclosing aninternal chamber 40 having a generally flat lower surface 41 and agenerally flat upper surface 42. A protuberance 39a extending upwardlyfrom wall 39 is provided for purposes to be hereinafter explained. Thediameter of the circular member is such that it fits nicely within thecylindrical chamber member 13 and such that when it is brought down onthe basket the flat lower surface wall 41 rests on a circular ring 36into which the upper rim of the basket 37 is fitted. The ring 36 is inthe form of a resilient O-ring which rests on the ledge 15. Thus whenthe floatable member 38 comes down on the O-ring, the O- ring acts as aseal and the member 38 thereby acts as a partition which seals off theupper tank portion 13 from the lower tank portion 14.

The floatable partition 38 is provided with a cylindrical opening 43passing through it from top to bottom and normally sealed closed by asealing plug 44. This provision, of the plug 44 in the opening is for apurpose to be explained later.

The weight of the member 38 in relation to its volume is such that itwill float at the water surface 22a in upper tank portion 13 with asubstantial portion riding below the water level. The level at which themember floats in the water can be adjusted as desired by the presence orabsence of some filling material in the interior chamber 40. Thus, whenthe water level in 22a in tank 13 drops down close to the top of thebasket 37 the lower wall 41 of the member will rest on sealing ring 36.

The lower chamber 14 has two sources of supply. One is the water flowinginto tank 12 through conduit 26 from the vortex. The second source is anequalizer inlet 45 which communicates with the pool water at a level farenough below its normal level that it will not suck air. Ordinarily theconduit 45 will communicate with the pool water at the main drain at thebottom of the pool. Conduit 45 is brought through the bottom wall 14a oflower tank portion 14 and up through the bottom of basket 37 which isformed with a reentrant conical portion 37a extending up from the bottomof the basket and tapering inwardly to join the conduit 45 near the topof the conduit so that pool water entering the tank 12 in the directionof the arrow associated with conduit 45 will empty into the basket 37before flowing out of the tank through conduit 35.

Communication between the tank and the equalizer inlet line 45 can beclosed or regulated by a check valve mechanism 46 which may be suitableform. The particular form illustrated comprises a valve member 47adapted to rest on an annular seat 48 of the incoming conduit. The valvemember 47 is mounted on a stem 54 which passes through a threadedbushing 49 having a flange 50. Head 54a is mounted to the stem above thebushing. A spring 51 around the stem is compressed between the valvemember 47 and the bushing 49 is threaded into a cap 52 supported by anumber of columns extending upright from the conduit 45 and providingspaces therebetween through which water entering the basket from conduit45 may flow. By turning bushing 49 on its thread the flange 50 may bemoved downwardly to further compress the spring to regulate the amountof pressure exerted by valve 47 against the water incoming from conduit45. This will regulate the rate of flow of this water even to the pointof shutting it off entirely.

During normal skimming operation, the floatable member 38 floats at theposition shown in FIG. 1 at the water surface 22a in the tank. If thewater level 22 in the pool should drop substantially, for example tonear or below the level of point 29 of the vortex chamber, little or nowater would flow into the tank 12 through conduit 26 and the waterdelivered to the tank I2 from the vortex would have lost control, whichwould result in the emptying of tank 12 if it were not for the float 38and equalizer line 45 arrangement. When the level in tank 12 drops fromposition 224 to a lower position 22b, the floatable partition member 38coming down with the lowering water level will rest on O-ring 36 to sealoff the lower tank portion 14 from the upper tank portion 13, before anysubstantial air enters the lower portion 14. The pump suction willmaintain the partition 38 in its sealing position, and at the same timewill open check valve 47 if it is not already open; or if it be alreadyopen somewhat, will open it further, by the exertion of the requisiteforce upon the check valve. The pump is now supplied entirely by theline 45 through which water is flowing in the direction of the arrow, tomeet the demand of the pump.

it may sometimes be desired to operate the system with the check valve47 set so that during normal operation the entire demand of the pump ismet by the water supplied by the vortex chamber, in which case no waterenters the tank 12 from the equalizer conduit 45. Under othercircumstances it may be desired to supply the tank 12 both from thevortex chamber and from the equalizer line 45, in which case the checkvalve will usually be set so that about 15 percent of the water enteringtank 12 is from the equalizer line and percent from the vortex chamber,unless of course the vortex chamber becomes incapable of supplying thepump demand as when the pool water level drops, in which case the checkvalve opens sufficiently to permit the equalizer line 45 to supply theentire demand.

When the circulating pump is turned off the water in tank 12 is at thesame level as the level of the pool water and the float 38 is floatingat that level. When the pump is turned on for normal circulatingoperation it will draw water out of tank 12 which will lower the levelof water in the tank down to some level 22a at which vortex waterentering the tank from conduit 26 which together with the water fromequalizer 45, if any, will supply the pump and thereby hold the tankwater level at some equilibrium value lower than the level 22 of thepool water. Debris and dust and the like floating on the pool watersurface and entering the vortex chamber through entrance opening 20 willbe drawn into the vortex and thereby brought down with the vortex waterthrough conduit 26 into tank 12 where most of it will be prevented frompassing to the pump through conduit 34 by being caught in the debrisbasket 37. It will be recognized that the pool water level 22 should notbe allowed to go so high that an effective vortex will not form;otherwise debris could simply remain floating on top in the chamber.

FIG. 3 illustrates the water of the vortex itself as it is formed at thevortex cone or sink 25. Water from the pool surface 22 flows along theentrance path through entrance 20 and over the downwardly slopingentrance floor 24 in the direction of the arrow. The vortex chamber wallsection 27b deflects that portion of the water striking it, to adirection approximately tangential to the circular rim of the cone orsink. That portion of the incoming water striking wall section 270 willalso be deflected to a direction approximately tangential to the rim ofthe cone. This wall construction, together with the downward slope offloor 24 to the sink 25 augments the tendency to form the vortex. Theparticular construction of FIG. 2 results in a vortex which rotatescounterclockwise at the cone as illustrated in FIG. 3.

If it is desirable to vacuum the swimming pool, cover 18 may be removedfrom the skim tank and float 38 may be removed through the opening atthe top of the skim tank. Plug 44 is then removed from opening 43 of thefloat and the float is reinserted back into the skim tank in a positionupside down from that illustrated in FIG. I so that protuberance 39a isdisposed downwardly from the float. The vacuum hose (not shown) for thevacuum cleaner may be fitted into opening 43 and extend through theopening of the skim tank. Float 36 is forced downwardly through thewater in the tank so as to seal against O-ring seal 36. In thisposition, protuberance 39a contacts head 54a of the valve mechanism 46to prevent the valve from opening. Hence, during the vacuum operation,water is drawn through the vacuum head and vacuum hose (not shown)through opening d3 of float 36 and out through conduit 35 to the pump.The float body 36 prevents operation of the vortex portion of theskimmer, and protuberance 39a prevents valve 4-6 from opening so thatwater will not enter from the equalizer line 45. Hence, during thevacuuming operation substantially all suction of the pump (not shown)will be applied to the vacuum line.

The embodiment of FIG. 4 is somewhat similar to that of FIGS. 1 and 2 inthat a vortex chamber built and arranged in reference to the pool likethat in FIGS. l and 2 is used together with its exit conduit 26. Theskim tank 60 is quite similar to the tank 12 of FIG. I but differs inthat the conduit 45 of FIG. 1 is omitted and correspondingly the basket6ll in FIG. 6 is of the ordinary type without the reentrant portionshown as 370 in FIG. II. The conduit elements 34 and 35 leading to thepump inlet can be the same as in FIG. I. In FIG. 4i the floatableelement or partition 62 is constructed and functions similar to thefloatable member 38 of FIG. 1 but differs in that the element 62 isprovided with a central opening 63 through it into which there isinserted the lower end ofa bellows hose 64 The upper end of the bellowsconnects with a conduit 65 which communicates with the pool water,ordinarily at the main drain at the bottom of the pool.

When the circulating pump is being operated, and the tank 60 isreceiving water through conduit 26 from the vortex being created in thechamber, the float 62 is up off the top of the basket in the positionshown in FIG. 4. When, however, the water level in the tank 60 drops asby lowering of the pool water level the float comes down with thedropping water level in the tank until it seats on O-ring 36 at the topof the basket in a manner similar to the sealing of the float 3% in FIG.ll. Since the conduit 65 is held in its fixed position near the top ofthe tank as shown in FIGS. 4 and 5, the bellows 64l distends as shown inFIG. 5.

It will be recognized that use of a vortex according to the presentinvention makes it possible to eliminate the usual mechanical orfloating weir for skimming a pool. As the vortex performs a functionmuch like that of a mechanical or floating weir, it may aptly bereferred to as a vortex weir." The use of the vortex according to thisinvention is not limited to use with the particular tanks illustratedand described herein, which are given for the purpose of example ratherthan of limitation.

The vortex may be used to send pool surface water to other locationsoutside the pool such as for example tanks or regions of differenttypes. Ordinarily, of course, it will be desired to incorporate thevortex as part of a circulatory system by which pool surface water ispumped through a filter and sent back to the pool. Skim tank 12 may belocated some distance from the pool wall, and may even be adjacent thefilter. In such case, conduit 26 is extended to provide connectionbetween the vortex chamber 19 and skim tank I2. Thus, the deck 17 of thepool is not obstructed by the cover of the skim tank.

It will be recognized also that modifications may be made withoutdeparting from the scope of the invention. For example, the vortexchamber need not be constructed precisely as illustrated in thedrawings. While the area of the vortex is illustrated as the cone 25which acts as a sink for the vortex, some other form of sink may be usedwhich will produce the vortex, for example a sink with curved sides.

I claim:

I. In a skimmer for skimming liquid with floating debris, if present,from the surface of a pool, a vortex chamber having a floor, an entranceto the floor and an exit opening from the floor, said floor slopingdownwardly and inwardly to the exit opening from an upper and outerregion of the floor at the entrance, to form a sink which emptiesdownwardly through the exit opening, said entrance being adapted forpassage of surface liquid from the pool to the chamber, and beingconstructed and arranged to direct incoming liquid from the pool to thechamber floor in a downward direction and with a tangential componentrelative to the exit opening, thereby augrnenting the tendency of theincoming liquid to flow in the form of a vortex at the chamber floordown to the exit opening so that the liquid passing through the exitopening carries debris with it.

2. Apparatus according to claim II in which the entrance communicateswith the floor and is provided with wall means positioned to allow theentrance to direct the incoming liquid substantially tangential to thesink, so that the incoming pool liquid forms the vortex commencing at ornear the level of the pool surface from where it extends down into thesink to the exit opening.

3. Apparatus according to claim I in which the sink floor issubstantially frustoconical.

41. Apparatus according to claim l in which the entrance has an entrancefloor inclined relative to the horizontal, and one side of said entrancefloor is higher than its other side and higher than the floor of thesink.

5. Apparatus according to claim 4 in which the-floor of the entrance isshaped to form substantially a continuation of the shape of the sinkfloor.

6. Apparatus according to claim 4 in which the wall means includes awall portion at the side of the entrance opposite the higher side of theentrance floor.

7. Apparatus according to claim 6 in which the wall means includes awall portion at the same side of the entrance as the higher side of theentrance floor.

8. Apparatus according to claim l in which a receiving tank is connectedto said exit opening for receiving the liquid and debris from thevortex.

9. Apparatus according to claim 6 in which the receiving tank isprovided with means for withdrawing the liquid from it.

110. Apparatus according to claim 3 in which the receiving tank has anupper portion and a lower portion in communication with each other whenthe liquid is at a normal level in the upper portion and the connectionto tank from the exit opening leads into the upper portion, meansadapted to seal off the upper and lower portions from each other whenthe liquid level is abnormally low in the upper portion, an outlet fromthe lower portion adapted to be connected to the suction line of a pumpand a bypass conduit leading to the lower portion and operative when theupper and lower portions are sealed from each other, to supply liquidfrom a source to the lower portion and thereby supply the pump.

llll. Apparatus according to claim llfl in which the means adapted toseal off the upper and lower portions from each other comprises a floatseat at the junction of the upper and lower portions and a float abovethe float seat, which floats on the liquid in the upper portion at adistance above the seat during normal skimming operation, and whichfloats down on the seat when the liquid level in the upper portionrecedes due to reduced flow into it from the chamber.

12. Apparatus according to claim ill in which the float contains amember which blocks the entrance to the tank from the conduit when thefloat engages the seat.

113. In a skimmer for skimming surface water from a pool, a tank of thetype having an upper portion and a lower portion in communication witheach other when the water is at a normal level in the upper portion,means adapted to seal off the upper and lower portions from each otherwhen the water level is abnormally lower in the upper portion, an outletfrom the lower portion adapted to be connected to a suction line of apump, and a bypass conduit leading to the lower portion and operativewhen the upper and lower portions are sealed from each other, to supplywater from a source to the lower portion and thereby supplying the pump,said sealing off means comprising: a movable floatable body having anupper surface and a lower surface, within the upper tank portion, and aseat at the junction of the upper and lower tank portions on whicheither the upper or lower surfaces of the floatable body can rest toseal off the upper and lower portions from each other, said body havinga passage way through it from the upper to the lower surfaces, and aremovable plug closing said passage way to prevent flow of liquidthrough it when the lower surface of the body is engaging the seat inthe normal operating position of the floatable body, a valve meanslocated in the lower tank portion adapted to open when the upper andlower portions are sealed from each other by the lower surface of thefloatable body and also adapted to be actuated to a closed position toshut off flow through the bypass conduit, actuating means at the saidupper surface of said body positioned to engage and actuate the valvemeans to shut the valve means when the body is inverted from the normaloperating position so that when the body is placed so that said uppersurface engages the seat, in said inverted position, the actuating meansactuates said valve means, whereby a vacuum hose fitted to said openingwhen the plug is removed, can draw water from the pool in a cleaningprocess and send said water through the opening into the lower tankportion to supply the pump.

14. Apparatus according to claim 13 in which the actuating means is aprotuberance at the upper surface of the floatable body.

15. In a skimmer for skimming liquid with floating debris, if present,from the surface of a pool, a chamber having a floor provided with anexit opening, said exit opening being within the floor, said chamber andfloor. being positioned, constructed and arranged so that liquid fromthe pool surface flows into the chamber and onto the floor, so that theliquid entering the chamber forms a vortex at and above the exitopening, a receiving tank connected to said exit opening for receivingthe liquid and debris from the vortex, said receiving tank having anupper portion and a lower portion in communication with each other whenthe liquid is at a normal level in the upper portion, said connection tothe tank from the exit opening communicating with said upper portion,means adapted to seal off the upper and lower portions from each otherwhen the liquid level is abnormally low in the upper portion, an outletfrom the lower portion adapted to be connected to the suction line of apump and a bypass conduit leading to the lower portion and operativewhen the upper and lower portions are sealed from each other, to supplyliquid from a source to the lower portion and thereby supply the pump.

0-188]. (Swimquip) mg? 6 .UNITED STATES PATENT OFFICE CERTIFICATE OFCORRECTION Patent No. 3,623,664 Dated December 21, 1971.

Inventor (s) Dav id A Stanwood It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

r- In the Patent I Q Column 1, line 29 "flows" should be --flow line 46"inducting" should be --inducing- Column 2, line 47 "nd" should be-'-and--= 57 after "in" insert --the-- Column 3 line 2 "paths" should be--path-- line 17 "24" should be --26-- line 38 after "provision" cancelthe comma line 46 cancel "in" line 66 after "be" insert --any-- line 72after "49" insert ---which-- line 73 after "columns" insert --53--Column 4, line 15 "line" should be --conduit-- line 26 "line" should be--conduit-- line 48 cancel "which" Column 5, line 9 after "the", (firstoccurrence) insert --top Signed and sealed this 27th. day of June 1972.

(SEAL) Attest:

LEDNARD H-FLE'IC HER JR ROBERT GOTTSCHALK J Attesting OfficerCommissioner of Patents

1. In a skimmer for skimming liquid with floating debris, if present,from the surface of a pool, a vortex chamber having a floor, an entranceto the floor and an exit opening from the floor, said floor slopingdownwardly and inwardly to the exit opening from an upper and outerregion of the floor at the entrance, to form a sink which emptiesdownwardly through the exit opening, said entrance being adapted forpassage of surface liquid from the pool to the chamber, and beingconstructed and arranged to direct incoming liquid from the pool to thechamber floor in a downward direction and with a tangential componentrelative to the exit opening, thereby augmenting the tendency of theincoming liquid to flow in the form of a vortex at the chamber floordown to the exit opening so that the liquid passing through the exitopening carries debris with it.
 2. Apparatus according to claim 1 inwhich the entrance communicates with the floor and is provided with wallmeans positioned to allow the entrance to direct the incoming liquidsubstantially tangential to the sink, so that the incoming poOl liquidforms the vortex commencing at or near the level of the pool surfacefrom where it extends down into the sink to the exit opening. 3.Apparatus according to claim 1 in which the sink floor is substantiallyfrustoconical.
 4. Apparatus according to claim 1 in which the entrancehas an entrance floor inclined relative to the horizontal, and one sideof said entrance floor is higher than its other side and higher than thefloor of the sink.
 5. Apparatus according to claim 4 in which the floorof the entrance is shaped to form substantially a continuation of theshape of the sink floor.
 6. Apparatus according to claim 4 in which thewall means includes a wall portion at the side of the entrance oppositethe higher side of the entrance floor.
 7. Apparatus according to claim 6in which the wall means includes a wall portion at the same side of theentrance as the higher side of the entrance floor.
 8. Apparatusaccording to claim 1 in which a receiving tank is connected to said exitopening for receiving the liquid and debris from the vortex. 9.Apparatus according to claim 8 in which the receiving tank is providedwith means for withdrawing the liquid from it.
 10. Apparatus accordingto claim 8 in which the receiving tank has an upper portion and a lowerportion in communication with each other when the liquid is at a normallevel in the upper portion and the connection to tank from the exitopening leads into the upper portion, means adapted to seal off theupper and lower portions from each other when the liquid level isabnormally low in the upper portion, an outlet from the lower portionadapted to be connected to the suction line of a pump and a bypassconduit leading to the lower portion and operative when the upper andlower portions are sealed from each other, to supply liquid from asource to the lower portion and thereby supply the pump.
 11. Apparatusaccording to claim 10 in which the means adapted to seal off the upperand lower portions from each other comprises a float seat at thejunction of the upper and lower portions and a float above the floatseat, which floats on the liquid in the upper portion at a distanceabove the seat during normal skimming operation, and which floats downon the seat when the liquid level in the upper portion recedes due toreduced flow into it from the chamber.
 12. Apparatus according to claim11 in which the float contains a member which blocks the entrance to thetank from the conduit when the float engages the seat.
 13. In a skimmerfor skimming surface water from a pool, a tank of the type having anupper portion and a lower portion in communication with each other whenthe water is at a normal level in the upper portion, means adapted toseal off the upper and lower portions from each other when the waterlevel is abnormally lower in the upper portion, an outlet from the lowerportion adapted to be connected to a suction line of a pump, and abypass conduit leading to the lower portion and operative when the upperand lower portions are sealed from each other, to supply water from asource to the lower portion and thereby supplying the pump, said sealingoff means comprising: a movable floatable body having an upper surfaceand a lower surface, within the upper tank portion, and a seat at thejunction of the upper and lower tank portions on which either the upperor lower surfaces of the floatable body can rest to seal off the upperand lower portions from each other, said body having a passage waythrough it from the upper to the lower surfaces, and a removable plugclosing said passage way to prevent flow of liquid through it when thelower surface of the body is engaging the seat in the normal operatingposition of the floatable body, a valve means located in the lower tankportion adapted to open when the upper and lower portions are sealedfrom each other by the lower surface of the floatable body and alsoadapted to be actuated to a closed position to shut off flow through theBypass conduit, actuating means at the said upper surface of said bodypositioned to engage and actuate the valve means to shut the valve meanswhen the body is inverted from the normal operating position so thatwhen the body is placed so that said upper surface engages the seat, insaid inverted position, the actuating means actuates said valve means,whereby a vacuum hose fitted to said opening when the plug is removed,can draw water from the pool in a cleaning process and send said waterthrough the opening into the lower tank portion to supply the pump. 14.Apparatus according to claim 13 in which the actuating means is aprotuberance at the upper surface of the floatable body.
 15. In askimmer for skimming liquid with floating debris, if present, from thesurface of a pool, a chamber having a floor provided with an exitopening, said exit opening being within the floor, said chamber andfloor. being positioned, constructed and arranged so that liquid fromthe pool surface flows into the chamber and onto the floor, so that theliquid entering the chamber forms a vortex at and above the exitopening, a receiving tank connected to said exit opening for receivingthe liquid and debris from the vortex, said receiving tank having anupper portion and a lower portion in communication with each other whenthe liquid is at a normal level in the upper portion, said connection tothe tank from the exit opening communicating with said upper portion,means adapted to seal off the upper and lower portions from each otherwhen the liquid level is abnormally low in the upper portion, an outletfrom the lower portion adapted to be connected to the suction line of apump and a bypass conduit leading to the lower portion and operativewhen the upper and lower portions are sealed from each other, to supplyliquid from a source to the lower portion and thereby supply the pump.